Patent Literature 1: JP 2001-319297 A
A conventional technology is known which guides an emergency vehicle to an emergency site that is an occurrence position of an emergency situation. For instance, Patent Literature 1 discloses a technology as follows. A center apparatus retrieves some route information to guide a fire truck to a fire site from a variety of information collected and transmits the retrieved route information wirelessly. Meanwhile, the fire truck, which receives the route information from the center apparatus, displays the received route information in a display apparatus.
The technology disclosed in Patent Literature 1 thus transmits the route information retrieved from a variety of information collected in the center apparatus. For instance, the information may be collected after confirming an occurrence of an emergency situation. This needs a time period from when confirming the occurrence of the emergency situation to when transmitting the route information. This may not permit a quick dispatch of a fire truck to an emergency site in spite of emergency.
In contrast, the information may be collected in advance before an occurrence of an emergency situation. This may, however, deteriorate a freshness of the collected information, so that the route information which does not meet a recent state around an emergency site may be retrieved and transmitted by the center apparatus. For instance, a road segment included in the route information may be incidentally in an impassable state owning to a parked vehicle or an object over the road segment. Such a case may eventually transmit the route information including the impassable road segment. The occupant of an emergency vehicle running along the route information transmitted from the center apparatus may necessarily stop and return at the impassable road segment, therefore needing to go to the emergency site while independently searching for a route to reach the emergency site.